U.S. patent number 7,406,737 [Application Number 10/850,383] was granted by the patent office on 2008-08-05 for washing machine and control method thereof.
This patent grant is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Seung Ju Choi, Hyun Sook Kim, Hyung Gyoon Kim, Seong Min Oak, Jae-Ryong Park, Seon-Woo Park, Sang Yeon Pyo, Byoung Yull Yang, Hye Soon Yang.
United States Patent |
7,406,737 |
Yang , et al. |
August 5, 2008 |
Washing machine and control method thereof
Abstract
A drum type washing machine in which wash water and laundry
contained in a rotating tub are heated by steam supplied into the
rotating tub, so as to rapidly increase the temperature of the wash
water and laundry, thereby being capable of reducing the total wash
time while reducing the amount of wash water to be used, and
reducing the consumption of energy caused by heating of the wash
water. The washing machine includes a steam generating unit for
heating water supplied thereto, thereby generating steam, and a
control unit for rotating the rotating tub at a high speed to cause
the laundry contained in the rotating tub to be in constant contact
with an inner peripheral surface of the rotating tub without
falling down, by virtue of a centrifugal force generated during the
rotation of the rotating tub, the control unit supplying the steam
from the steam generating unit into the rotating tub during the
high-speed rotation of the rotating tub, to increase the internal
temperature of the rotating tub and the temperature of the
laundry.
Inventors: |
Yang; Byoung Yull (Ansan-Si,
KR), Kim; Hyung Gyoon (Suwon-Si, KR), Pyo;
Sang Yeon (Suwon-Si, KR), Park; Seon-Woo
(Suwon-Si, KR), Yang; Hye Soon (Yongin-Si,
KR), Oak; Seong Min (Masan, KR), Choi;
Seung Ju (Suwon-Si, KR), Park; Jae-Ryong
(Suwon-Si, KR), Kim; Hyun Sook (Suwon-Si,
KR) |
Assignee: |
Samsung Electronics Co., Ltd.
(Suwon-si, KR)
|
Family
ID: |
34617438 |
Appl.
No.: |
10/850,383 |
Filed: |
May 21, 2004 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050132503 A1 |
Jun 23, 2005 |
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Foreign Application Priority Data
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Dec 23, 2003 [KR] |
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10-2003-0095535 |
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Current U.S.
Class: |
8/158; 68/12.22;
68/12.18 |
Current CPC
Class: |
D06F
39/008 (20130101); D06F 35/006 (20130101); Y02B
40/00 (20130101) |
Current International
Class: |
D06F
35/00 (20060101) |
Field of
Search: |
;68/12.18,12.22
;8/158 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1275767 |
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Jan 2003 |
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EP |
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EP 0496708 |
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Jul 1992 |
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IT |
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48-36785 |
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Nov 1973 |
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JP |
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04-158896 |
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Jun 1992 |
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JP |
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Primary Examiner: Barr; Michael
Assistant Examiner: Heckert; Jason
Attorney, Agent or Firm: Sughrue Mion, PLLC
Claims
What is claimed is:
1. A control method for a washing machine including a rotating tub
for washing laundry contained therein in accordance with rotation
thereof, and a steam generating unit for heating water supplied
thereto, thereby generating steam, the control method comprising:
supplying a detergent solution to the rotating tub after applying
wash water to the rotating tub; rotating the rotating tub at a high
speed causing the laundry wetted with detergent and wash water
contained in the rotating tub to be in constant contact with an
inner peripheral surface of the rotating tub without falling down,
by virtue of a centrifugal force generated during the rotation of
the rotating tub; and supplying the steam from the steam generating
unit into the rotating tub during the high-speed rotation of the
rotating tub, to increase an internal temperature of the rotating
tub and the laundry wetted with detergent and wash water; wherein
the detergent solution and the steam are supplied during a same
wash course prior to a spin-dry cycle.
2. The control method according to claim 1, further comprising:
heating the wash water by the steam supplied into the rotating
tub.
3. The control method according to claim 1, further comprising:
reducing the rotating speed of the rotating tub, after the
high-speed rotation of the rotating tub for a predetermined time,
to rotate the rotating tub at a low speed causing the laundry to
fall down in the rotating tub, so that the laundry is displaced in
position.
4. The control method according to claim 3, wherein the high-speed
rotation and low-speed rotation of the rotating tub are carried out
in an alternate manner.
5. The control method according to claim 1, wherein the rotating
tub is rotated in forward and reverse directions in an alternate
manner, while reducing a rotating speed thereof between a duration,
in which the rotating tub rotates in the forward direction, and a
duration, in which the rotating tub rotates in the reverse
direction, to rotate at a low speed causing the laundry to fall
down therein, so that the laundry is displaced in position.
6. A control method for a washing machine including a rotating tub
for washing laundry contained therein in accordance with rotation
thereof, and a steam generating unit for heating water supplied
thereto, thereby generating steam, the control method comprising:
supplying wash water into the rotating tub, prior to a high-speed
rotation of the rotating tub, to wet the laundry by the wash water;
injecting a detergent solution onto the laundry after completion of
the supply of wash water into the rotating tub; rotating the
rotating tub at a high speed causing the laundry wetted with
detergent and wash water contained in the rotating tub to be in
constant contact with an inner peripheral surface of the rotating
tub without falling down, by virtue of a centrifugal force
generated during the rotation of the rotating tub; and supplying
the steam from the steam generating unit into the rotating tub
during the high-speed rotation of the rotating tub, to increase an
internal temperature of the rotating tub and the laundry wetted
with detergent and wash water; wherein detergent solution and the
steam are supplied during a same wash course prior to a spin-dry
cycle.
7. The control method according to claim 6, further comprising:
supplying water to a detergent supply unit; dissolving a detergent
in the water in the detergent supply unit to prepare the detergent
solution, and storing the prepared detergent solution in the
detergent supply unit before injecting the detergent solution onto
the laundry.
8. A control method for a washing machine, the control method
comprising: supplying a detergent solution to the rotating tub
after a wash water has been supplied to the rotating tub; rotating
a rotating tub at a high speed causing laundry wetted with
detergent and wash water contained in the rotating tub to be in
contact with an inner peripheral surface of the rotating tub
without falling down; and supplying steam into the rotating tub
during the high-speed rotation of the rotating tub containing the
laundry wetted with detergent and wash water, wherein the detergent
solution and the steam are supplied during a same wash course.
9. The control method according to claim 8, further comprising:
supplying wash water into the rotating tub, prior to the high-speed
rotation of the rotating tub, to wet the laundry by the wash water,
and heating the wash water by the steam supplied into the rotating
tub.
10. The control method according to claim 8, further comprising:
reducing the rotating speed of the rotating tub, after the
high-speed rotation of the rotating tub for a predetermined time,
to rotate the rotating tub at a low speed causing the laundry to
fall down in the rotating tub, so that the laundry is displaced in
position.
11. The control method according to claim 10, wherein the
high-speed rotation and low-speed rotation of the rotating tub are
carried out in an alternate manner.
12. The control method according to claim 8, wherein the rotating
tub is rotated in forward and reverse directions in an alternate
manner, while reducing a rotating speed thereof between a duration,
in which the rotating tub rotates in the forward direction, and a
duration, in which the rotating tub rotates in the reverse
direction, to rotate at a low speed causing the laundry to fall
down therein, so that the laundry is displaced in position.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of Korean Patent Application
No. 2003-95535, filed on Dec. 23, 2003 in the Korean Intellectual
Property Office, the disclosure of which is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
Apparatuses and methods consistent with the present invention
relate to a washing machine and, more particularly, to a washing
machine wherein wash water is heated so that wash and rinse cycles
are carried out, using hot water.
2. Description of the Related Art
Drum type washing machines, in which laundry is raised, together
with wash water, along a cylindrical rotating tub containing the
laundry and wash water, and subsequently falls down, during
rotation of the cylindrical rotating tub, such that it is washed by
virtue of an impact applied thereto when it falls down, are well
known. Such a drum type washing machine includes a water tub for
containing wash water, a rotating tub rotatably mounted in the
water tub, and provided with through holes for spin-drying at a
peripheral wall thereof, and a heater for heating the wash water
contained in the water tub. During a wash cycle of the drum type
washing machine, washing of laundry is carried out as the rotating
tub rotates within the water tub at a relatively low speed under
the condition in which wash water and detergent have been supplied
into the water tub. In order-to effectively wash the laundry, the
wash water is used in the wash cycle in a state of being heated by
the heater.
However, such a conventional washing machine has a problem in that
a great deal of time is required to heat the wash water to a
desired wash temperature because a large amount of wash water
contained in the water tub is heated entirely by the heater, which
is disposed at the bottom of the water tub, so that the overall
wash time is increased.
Furthermore, the conventional washing machine involves waste of
wash water because the wash water fills even a heater case
installed at the bottom of the water tub. Waste of energy is also
caused by the fact that it is necessary to heat the water contained
in the heater case.
SUMMARY OF THE INVENTION
Illustrative, non-limiting embodiments of the present invention
overcome the above disadvantages and other disadvantages not
described above. Also, the present invention is not required to
overcome the disadvantages described above, and an illustrative,
non-limiting embodiment of the present invention may not overcome
any of the problems described above.
Therefore, it is an aspect of the invention is to provide a drum
type washing machine in which wash water and laundry contained in a
rotating tub are heated by steam supplied into the rotating tub, so
as to rapidly raise the temperature of the wash water and laundry,
thereby being capable of reducing the total wash time while
reducing the amount of wash water to be used, and reducing the
consumption of energy caused by heating of the wash water.
Another aspect of the invention is to provide a control method for
the drum type washing machine adapted to accomplish the above
object of the invention, which is capable of reducing the total
wash time while reducing the amount of wash water to be used, and
the consumption of energy caused by heating of the wash water.
In accordance with one aspect, the present invention provides a
washing machine comprising: a rotating tub which washes laundry
contained therein in accordance with rotation thereof; a steam
generating unit which heats water supplied thereto, thereby
generating steam; and a control unit which controls rotation of the
rotating tub at a high speed causing the laundry contained in the
rotating tub to be in constant contact with an inner peripheral
surface of the rotating tub without falling down, by virtue of a
centrifugal force generated during the rotation of the rotating
tub, the control unit controlling supply of the steam from the
steam generating unit into the rotating tub during the high-speed
rotation of the rotating tub, to increase an internal temperature
of the rotating tub.
In accordance with another aspect, the present invention provides a
control method for a washing machine, the control method comprising
the steps of: rotating a rotatable tub at a high speed causing
laundry contained in the rotating tub to be in contact with an
inner peripheral surface of the rotating tub without falling down,
and supplying steam into the rotating tub during the high-speed
rotation of the rotating tub, to increase an internal temperature
of the rotating tub.
In accordance with another aspect, the present invention provides a
control method for a washing machine including a rotating tub for
washing laundry contained therein in accordance with rotation
thereof, and a steam generating unit for heating water supplied
thereto, thereby generating steam, the control method comprising
the steps of: rotating the rotating tub at a high speed causing the
laundry contained in the rotating tub to be in constant contact
with an inner peripheral surface of the rotating tub without
falling down, by virtue of a centrifugal force generated during the
rotation of the rotating tub; and supplying the steam from the
steam generating unit into the rotating tub during the high-speed
rotation of the rotating tub, to increase an internal temperature
of the rotating tub.
In accordance with still another aspect, the present invention
provides a control method for a washing machine including a
rotating tub for washing laundry contained therein in accordance
with rotation thereof, and a steam generating unit for heating
water supplied thereto, thereby generating steam, the control
method comprising the steps of: supplying wash water into the
rotating tub, prior to the high-speed rotation of the rotating tub,
to wet the laundry by the wash water; rotating the rotating tub at
a high speed causing the laundry contained in the rotating tub to
be in constant contact with an inner peripheral surface of the
rotating tub without falling down, by virtue of a centrifugal force
generated during the rotation of the rotating tub; and supplying
the steam from the steam generating unit into the rotating tub
during the high-speed rotation of the rotating tub, to increase an
internal temperature of the rotating tub.
BRIEF DESCRIPTION OF THE DRAWINGS
The above aspects, and other features and advantages of the present
invention will become more apparent after reading the following
detailed description when taken in conjunction with the drawings,
in which:
FIG. 1 is a sectional view illustrating the configuration of a drum
type washing machine according to an exemplary embodiment of the
present invention;
FIG. 2 is a block diagram illustrating a control system of the drum
type washing machine shown in FIG. 1;
FIG. 3 is a flow chart illustrating a control method for a drum
type washing machine in accordance with an exemplary embodiment of
the present invention;
FIG. 4 is a flow chart illustrating the process of heating laundry
and wash water at step 310 in the drum type washing machine control
method shown in FIG. 3; and
FIGS. 5A to 5D are schematic views illustrating respective states
of the laundry in the rotating tub varying in accordance with the
control method shown in FIG. 4.
DETAILED DESCRIPTION OF ILLUSTRATIVE, NON-LIMITING EMBODIMENTS OF
THE INVENTION
An illustrative, non-limiting embodiment of the present invention
will now be described in detail with reference to FIGS. 1 to 4.
FIG. 1 is a sectional view illustrating the configuration of a drum
type washing machine according to an exemplary embodiment of the
present invention. As shown in FIG. 1, the drum type washing
machine includes a cabinet 120, a drum-shaped water tub 122 mounted
in the cabinet 120, and adapted to contain wash water, and a
drum-shaped rotating tub 124 rotatably mounted in the water tub
122.
The rotating tub 124 has a rotating shaft 126 fixedly mounted to
the central portion of a rear wall thereof. The rotating shaft 126
is rotatably coupled to the central portion of a rear wall of the
water tub 122, so that the rotating tub 124 is rotatable within the
water tub 122. A plurality of through holes 124b are provided at a
peripheral wall of the rotating tub 124. A plurality of lifters 128
are provided at the inner surface of the rotating tub 124 at the
peripheral wall thereof in order to cause laundry contained in the
rotating tub 124 to repeatedly rise and fall down during rotation
of the rotating tub 124.
A driving unit, for example, a motor 130, is mounted to the rear
wall of the water tub 122 outside the water tub 122, so as to
rotate the rotating shaft 126 mounted to the rotating tub 124. An
access opening 132 is formed at a front wall of the cabinet 120.
The access opening 132 is aligned with access openings 122a and
124a respectively formed at the water tub 122 and rotating tub 124,
so as to allow the user to put laundry into the rotating tub 124
and to take laundry out of the rotating tub 124. Mounted to the
access opening 132 is a door 134 adapted to open and close the
access opening 132.
Arranged at an upper portion of the water tub 122 are a detergent
supply unit 136, a steam generating unit 160, and a water supply
unit 140. The detergent supply unit 136 serves to supply detergent
into the water tub 122, the steam generating unit 160 serves to
supply steam and hot water into the water tub 122, and the water
supply unit 140 serves to supply water to both the water tub 122
and the steam generating unit 160. A drainage unit 138 is mounted
at a lower portion of the water tub 122 in order to drain water
from the water tub 122. The drainage unit 138 includes a drainage
tube 138a, a drainage valve 138b, and a drainage motor 138c.
In FIG. 1, reference numeral 104 designates a steam supply valve,
and reference numerals 144 and 150 designate first and second water
supply valves, respectively. Also, reference numeral 184 designates
a wash water supply valve.
When the washing machine starts to operate under the condition in
which laundry has been put into the rotating tub 124, and detergent
has been put into the detergent supply unit 136, the first and
second water supply valves 144 and 150 are opened under control of
a control unit (FIG. 2), so that water is supplied to both the
detergent supply unit 136 and the steam generating unit 160. The
detergent put into the detergent supply unit 136 is supplied to the
water tub 122 in a state of being dissolved in the water supplied
to the detergent supply unit 136, as the water is introduced into
the water tub 122 via the detergent supply unit 136.
Meanwhile, the steam supply valve 104, which is connected between
the steam generating unit 160 and the rotating tub 124, is
initially maintained in a closed state. Accordingly, the water
supplied to the steam supply unit 160 fills a heating tank 162
included in the steam supply unit 160. Once water fills the heating
tank 162, it is heated by a heater (FIG. 2) installed in the
heating tank 162, thereby generating steam. When steam is
generated, the control unit (FIG. 2) opens the steam supply valve
104, thereby causing the steam to be introduced into the water tub
122. Thus, the wash water contained in the water tub 122 is heated
by the steam. This steam supply operation is continued until the
temperature of the wash water in the water tub 122 increases to a
predetermined wash temperature. For example, where the
predetermined wash temperature is 60.degree. C., steam is
continuously supplied until the wash water in the water tub 122 is
heated to 60.degree. C. by the supplied steam. In this case, the
water level and water temperature in the water tub 122 are sensed
by separate water level and temperature sensors (FIG. 2) installed
at the water tub 122, respectively. The wash water supply valve 184
is adapted to supply wash water in an unheated state to the water
tub 122.
FIG. 2 is a block diagram illustrating a control system of the drum
type washing machine shown in FIG. 1. Referring to FIG. 2, a
control unit 202 is illustrated which controls the overall
operation of the washing machine involving, for example, wash,
rinse, spin-dry, and dry cycles. Connected to an input of the
control unit 202 are a water level sensor 204, a temperature sensor
206, and an input unit 208. The water level sensor 204 detects the
amount of wash water supplied to the water tub 122, whereas the
temperature sensor 206 serves to detect the temperature of the wash
water supplied to the water tub 122. The input unit 208 allows the
user to set a desired wash course, or to select a desired
cycle.
A driving unit 210 is connected to an output of the control unit
202. The driving unit 210 drives various elements of the washing
machine, for example, the motor 130, drainage unit 138, heater 212,
first and second water supply valves 144 and 150, and steam supply
valve 104. The heater 212 is adapted to heat water filling the
heating tank 162, thereby generating steam. The first and second
water supply valves 144 and 150 are adapted to allow the water
supplied from the water supply unit 140 to be introduced into the
water tub 122 and steam generating unit 160, respectively. The
steam supply valve 104 serves to supply steam generated in the
steam generating unit 160 to the water tub 122.
In order to heat wash water and laundry contained in the water tub
122 prior to execution of a wash cycle, the control unit 202
performs a control operation for supplying steam generated in the
steam generating unit 160 to the water tub 122. In this case,
heating of laundry means heating of wash water absorbed in the
laundry. In order to rapidly and uniformly heat the laundry, steam
for heating the laundry is supplied under the condition in which
the laundry is uniformly in contact with the inner peripheral
surface of the rotating tub 124 by virtue of a centrifugal force
generated as the rotating tub 124 rotates at a high speed
sufficient to prevent the laundry from falling down. This can be
achieved by a control method according to an exemplary embodiment
of the present invention. This control method will now be described
in conjunction with FIGS. 3 to 6.
FIG. 3 is a flow chart illustrating a control method for a drum
type washing machine in accordance with an exemplary embodiment of
the present invention. In accordance with this control method, as
shown in FIG. 3, when a steam wash course is set by the user (Step
302), the first and second water supply valves 144 and 150 are
opened, so that water is supplied to both the detergent supply unit
136 and the steam generating unit 160. The water supplied into the
detergent supply unit 136 dissolves detergent contained in the
detergent supply unit 136. Thus, the detergent supply unit 136
stores a detergent solution having a desired detergent
concentration (Step 304a). Simultaneously, the wash water supply
valve 184 is opened, so that wash water is injected into the
rotating tub 124 to permeate into laundry contained in the rotating
tub 124 (Step 304b). After the process of injecting wash water onto
the laundry, the wash water supply valve 184 is closed.
Subsequently, the water supplied to the steam generating unit 160
is heated to generate steam.
Meanwhile, the detergent solution stored in the detergent supply
unit 136 is injected onto the laundry wetted in accordance with the
injection of wash water (Step 306). Since detergent is injected
onto the laundry in the form of the detergent solution, it is
possible to prevent the laundry from being stained by undissolved
detergent, and to avoid a degradation in wash effect. After
completion of the supply of wash water and the injection of
detergent, rotation of the rotating tub 124 is carried out in order
to uniformly mix the detergent with the wash water (Step 308). In
this case, the rotating tub 124 is alternately rotated in forward
and reverse directions in order to obtain an enhanced mixing
effect.
Following the complete supply of wash water and detergent, the
steam supply valve 104 is opened to supply steam into the rotating
tub 124. Since the rotating tub 124 is arranged inside the water
tub 122 while communicating with the water tub 122, the steam
supplied into the rotating tub 124 is also transferred to the water
tub 122. Thus, steam is supplied to both the rotating tub 124 and
the water tub 122. As a result, the wash water contained in the
water tub 122 and rotating tub 124 and the wash water and detergent
permeating the laundry contained in the rotating tub 124 are heated
by the supplied steam (Step 310).
After execution of step 310 for heating the laundry (including the
supplied detergent) using steam, a wash cycle involved in the set
steam wash course is executed (Step 312). At this time, additional
steam may be supplied, so as to maintain the interior of the
rotating tub 124 at a predetermined high temperature. After
completion of the wash cycle, rinse, spin-dry and dry cycles are
partially or entirely executed to complete the steam wash course
(Step 314).
In the control method illustrated in FIG. 3, it is important to
heat uniformly the laundry contained in the rotating tub 124 at the
step for heating wash water using steam. In particular, in the case
of a drum type washing machine, it is desirable to use a reduced
amount of wash water, in order to obtain a sufficient fall of
laundry in a rotating tub, because washing of the laundry is
achieved as the laundry falls down during rotation of the rotating
tub. In this case, most of the wash water supplied into the
rotating tub permeates into the laundry. In order to effectively
heat the wash water using steam, accordingly, it is necessary to
heat uniformly the laundry wetted by the wash water. Where the
rotating tub is rotated at low speed during the laundry heating
process, however, it is difficult to achieve uniform heating of the
laundry because the laundry is moved in a lumped state. In
accordance with the present invention, therefore, the rotating
direction and speed of the rotating tub 124 at the step of heating
laundry by steam is controlled to heat uniformly the laundry.
FIG. 4 is a flow chart illustrating the process of heating laundry
and wash water at step 310 in the drum type washing machine control
method shown in FIG. 3. In accordance with the present invention,
this process is carried out under the condition in which the
rotating tub 124 is alternately rotated at high speed in forward
and reverse directions in respective forward and reverse high-speed
rotation durations, while being rotated at low speed in a low-speed
rotation duration defined between the forward and reverse
high-speed rotation durations, so as to displace the position of
the laundry in the rotating tub 124.
In this process, as shown in FIG. 4, the rotating status, that is,
the rotating direction and speed, of the rotating tub 124 is first
detected (Step 402). Based on the detected result, it is determined
whether or not the rotating tub 124 rotates in one direction, for
example, the forward direction, at a high speed sufficient to cause
the laundry to be in constant contact with the inner peripheral
surface of the rotating tub 124 by virtue of a centrifugal force
generated in accordance with the rotation of the rotating tub 124
(Step 404). If it is determined at step 404 that the rotating tub
124 rotates at an insufficient speed, the rotating speed of the
rotating tub 124 is then increased to a predetermined high speed
(406). On the other hand, where the rotating tub 124 rotates at a
high speed sufficient to generate a centrifugal force preventing
the laundry from falling down, steam is supplied into the rotating
tub 124, so as to heat the laundry (Step 408). After the rotating
tub 124 rotates at high speed for a predetermined time (Step 410),
its rotating speed is decreased to a predetermined low speed, at
which the laundry falls down in the rotating tub 124 (Step 412). As
a result, the laundry, which rotates at the same speed as the
rotating tub 124 in a state of being in contact with the inner
peripheral surface of the rotating tub 124, falls down by virtue of
gravity, so that it is displaced in position while being turned
over. Accordingly, portions of the laundry not exposed to steam may
be directly exposed to the steam. After the low-speed rotation
duration, the rotating direction of the rotating tub 124 is
reversed. During the reverse rotation of the rotating tub 124,
steam is continuously supplied into the rotating tub 124, thereby
uniformly heating the entire portion of the laundry (Step 414). The
above procedure is repeatedly executed until the temperature of the
laundry, which may be measured based on the internal temperature of
the rotating tub 124, reaches a predetermined temperature (Step
416).
FIGS. 5A to 5D are schematic views illustrating respective states
of the laundry in the rotating tub varying in accordance with the
control method shown in FIG. 4. When the rotating tub 124 rotates
in the forward direction at high speed, as shown in FIG. 5A,
laundry 502 is uniformly distributed in the rotating tub 124 while
being in contact with the inner peripheral surface of the rotating
tub 124. As steam 504 comes into contact with the exposed surface
of the laundry 502, the laundry 502 is heated. If the high-speed
rotation of the rotating tub 124 is continuously carried out only
in one direction, it is difficult to achieve uniform heating of the
laundry 502 because the steam 504 comes into contact with only
one-side surface of the laundry 402. To this end, the rotating tub
124 is rotated at low speed after the high-speed rotation thereof
for a predetermined time. In accordance with the low-speed rotation
of the rotating tub 124, the laundry 502 falls down by virtue of
gravity, so that it is displaced in position, as shown in FIG. 5B.
Subsequently, the rotating tub 124 is rotated in a reverse
direction at high speed, so as to cause the laundry 502 to be
uniformly distributed in the rotating tub 124 while being in
contact with the inner peripheral surface of the rotating tub 124
(FIG. 5C). After a predetermined time elapses, the rotating tub 124
is rotated in the reverse direction at low speed, so as to displace
the position of the laundry 502 (FIG. 5D).
As apparent from the above description, in accordance with the
present invention, wash water and laundry contained in the rotating
tub are heated by steam supplied into the rotating tub.
Accordingly, it is possible to rapidly increase the temperature of
the wash water and laundry, thereby achieving a reduction in wash
time while reducing the amount of wash water to be used, and the
consumption of energy required to heat the wash water.
Although exemplary embodiments of the invention have been disclosed
for illustrative purposes, those skilled in the art will appreciate
that various modifications, additions and substitutions are
possible, without departing from the scope and spirit of the
invention as set forth in the accompanying claims.
* * * * *